I've been putting together a solar system recently. To save money, I've been using old car batteries out of my dad's junk pile.
Anyhow, one of the batteries I pulled out was bone dry. Having reviewed the threads, the 1st thing I did was fill the cells to the proper level with distilled water. A quick check with the voltmeter yielded a reading of around 3 volts.
I tried hooking it up to my Black and Decker 1A/2A smart charger (piece of crap that it is). It wouldn't turn on at all.
So, I tried using a version of this -- http://www.otherpower.com/images/scimages/556/watgas1.gif . After running for an hour, I managed to bring the voltage up to around 10 volts. So I hooked up the Black and Decker again -- it turns on, but cycles between green (charged) and yellow (charging) every 5 seconds. At least the red light (shorted) isn't lighting up. (I really wish I could find an old-fashioned transformered trickle charger like my dad used to have -- no "smart" technology or anything that gets things confused).
So I go back to the watgas1.gif circuit for another hour. It measures 10.8V. Same thing with the Black and Decker again. I leave the voltmeter hooked up to the batter for a couple of days, and the voltage goes down to 10V.
I hit the thing with the watgas1.gif circuit one more time, for 2 hours. At the end, the voltage check reads 9V.
So, what do you think? Did I ruin the battery (no loss if I did), or is there something else I should try? I haven't been to the parts store to get a hydrometer, so I have no idea what the SG is in the cells yet.
I'm about ready to remove the capacitor from the circuit and replace it with a 100W lightbulb, just to see what happens...